JPH10301234A - Photographic recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a printed image having resistance to wiping and scratching and having durability and solvent resistance by forming a photosensitive silver halide emulsion layer on one surface and forming a layer or a layer region containing a laser additive on the other side. SOLUTION: This photographic recording material has a substrate on which a photosensitive silver halide emulsion layer is formed on its one side and a layer or a layer region containing a laser additive is formed on another side (back side). The substrate is preferably a paper material with both surfaces coated with a polyethylene. The layer additive is a functional dyestuff which initiates the contrast enhancing reaction in a plastic material during impact by a laser. Changes in colors can be caused by dark coloring of a polymer matrix surrounding the pigment produced by partial carbonization. This process is caused mainly only in the dyestuff particles present near the surface, while more propagating damages to the matrix can be avoided. The photographic material is printed by using a laser coder based on a CO2 or YAG laser.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a photographic recording material having a support having at least one light-sensitive silver halide emulsion layer on one side and at least one layer or layer area which can be printed on the other side (back side). The support is preferably a paper material coated on both sides with polyethylene (PE).

[0002] Information on the back of photographic paper, such as the printing of the logo or text and numbers of the photographic paper manufacturer or processor's company, which the manufacturer or processor applies at its own request or at the consumer's desire. Are interested.

[0003] The printed images applied must be of very high quality. As far as possible, the printing operation should proceed at a speed that perfectly matches the speed of processing the image. The process must be environmentally friendly, have to be as flexible as possible, and be economical.

The back side of photographic paper is usually provided with an antistatic layer, which comprises a polymer electrolyte as an antistatic additive,
It consists of a binder system and additives such as hardeners and wetting agents.

[0005] This type of backside coating is designed so that it can be printed using printers such as ink ribbon printers, thermal printers and ink-jet printers used for image processing of photographic paper. However, nonetheless, the applied printed image is subjected to photographic processing. Rinsing and scuffing can reduce print quality. Therefore, improvements are still needed here.

[0006] What is needed is a wipe-and-scratch-resistant, durable and solvent-resistant printed image. In addition, high print quality, printing speed and flexibility and a high degree of environmental compatibility must be guaranteed.

[0007] It has now been found that these objects can be achieved if the backside contains a laser additive in at least one layer or one layer region and a laser printer is used for printing.

The present invention therefore relates to a photographic material of the type initially described, which also contains an effective amount of a laser additive in the backing PE laminate or in the internal material of the support.

These laser additives are functional pigments which initiate a contrast-increasing reaction in plastics during laser impact. This type of color change can be caused by darkening of the polymer matrix around the pigment resulting from partial carbonization, in which only the pigment particles near the surface are mainly involved, and more progressive damage to the substrate Can be excluded. However,
Color changes can also be caused by discoloration within the pigment itself. Finally, the visual change may be the result of foam formation on the surface. This is especially the case with plastics that have little or no tendency to carbonize. In the latter case, a white marking from light is formed. Depending on the type of plastic, pigment and laser, markings ranging from white to gray to black are possible.

[0010] Laser additives (laser-markable plastics) are described, for example, in EP 750 012, WO
95/30 546 and EP 718 378.

An example of a particularly suitable laser additive is Dar Dar
Iriodin ^R by Merck of Mstadt
It is sold under the trade name of LS pigment (LS = laser-sensitive). Further, these are treated with effect pigments (ef)
feature pigments), for example, Iriodin
By mixing with ^R- pearl luster pigments, a certain luster effect can also be obtained.

[0012] The introduction into the PE laminate layer can be effected by direct addition to the formulation. For example, 10 to 50
The additives can also be added as a masterbatch having an additive content of% by weight. A smaller amount of pigment active ingredient is sufficient to achieve the laser-induced contrast effect. As the bandwidth (as aba
nd width), in the range of 0.1 to 2.0% by weight. The addition has no significant effect on the material properties of the layer matrix. The rheology when laminating the PE layer is not affected. No streak or other side effects occur.

A prerequisite for laser coding is to use a laser whose radiation is outside the wavelength range of photosensitization. CO ₂ lasers and YAG lasers with wavelengths longer than 1000 nm are particularly suitable.

This type of laser has a high output power. They enable high printing speeds and sharp edge images to be achieved even for small images. The inscription can be provided, for example, via a pre-ordered mask, or on a moving typesetting copy, in the present case, on the back of the moving photographic strip. By refracting the laser beam in the xy directions, a variable printed image can also be provided. The inputs can be programmed via a computer program, thus promoting a high degree of flexibility.

[0015] Detailed Summary of processes described herein is shown in Merck's brochure regarding topics Iriodin ^R LS for laser marking of plastics.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Iriodin manufactured by Merck
^R LS 825 was introduced as a masterbatch into the PE laminate on the back side of a color negative photographic paper containing PE coated paper on both sides as a support. The products introduced are almost transparent pigments and the visual impression on the back of the photographic material remains substantially unchanged. The application amount is 0.2; 0.3;
4 and 0.6% by weight. Letters were marked using a YAG laser. An easy-to-read print image with a sharp edge having a medium gray tone was obtained. No damage occurred to the PE laminate, as was no photographic damage to the front photosensitive layer.

The main features and aspects of the present invention are as follows.

1. A photographic recording material having a support having at least one light-sensitive silver halide emulsion layer on one side and at least one layer or layer region containing a laser additive on the other side (back side).

2. 2. The photographic recording material according to claim 1, wherein the support is a paper coated on both sides with polyethylene.

3. The material described in the above 1 is CO ₂ or Y
A method for printing the back side of a photographic recording material, characterized by printing with a laser coder based on an AG laser.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Manfred Peters, Germany 51373 Leifelkusen Gutenberg Shuttlese 25

Claims (2)

[Claims] 1. A photographic recording material having a support having at least one light-sensitive silver halide emulsion layer on one side and at least one layer or layer region containing a laser additive on the other side (back side). 2. The method according to claim 1, wherein the material is CO ₂ or YA.
A method for printing the back side of a photographic recording material, characterized by printing with a laser coder based on a G laser.